The semiconductor industry has experienced rapid growth in recent years. Technological advances in semiconductor materials and design have produced various types of devices that serve different purposes. The fabrication of some types of these devices may require forming one or more III-V group compound layer on a substrate, for example forming a gallium nitride layer on a substrate. Devices using III-V group compounds may include light-emitting diode (LED) devices, laser diode (LD) devices, radio frequency (RF) devices, high electron mobility transistor (HEMT) devices, and/or high power semiconductor devices. Some of these devices, such as LED devices and LD devices, involve forming a quantum well having multiple pairs of active layers and barrier layers. The quantum well generates light when a voltage is applied. However, traditional LED and LD devices have quantum wells that have poor electron-hole recombination, thereby leading to reduced output power and large efficiency droop for the LED and LD devices.
Therefore, while existing LED and LD devices have been generally adequate for their intended purposes, they have not been entirely satisfactory in every aspect. LED and LD devices having better electron-hole recombination continue to be sought.